• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1641-1648
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• 2003

New and facile synthetic routes for preparation of optically active norephedrine, norpseudoephedrine and cathinone with high optical purities via double asymmetric induction by employing asymmetric reduction of 2-N-protected amino (or azido)-1-phenylpropanone and 2-methanesulfonyloxy-1-phenylpropanone with CBS-catalyzed-borane and $^dIpc_2BCl$ as chiral reducing agents are described.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1671-1672
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• 2005

• YAKHAK HOEJI
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• v.30 no.5
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• pp.214-219
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• 1986

A gas chromatographic procedure is described for the quantitative analysis of ephedrine hydrochloride, pseudoephediiiie hydrochloride and norephedrine hydrochloride in pharmaceutical preparations. The procedure was based upon the determination of thioureas formed from amines and phenylisothiocyanate. The recoveries of ephedrine, pseudoephedrine and norephedrine from pharmaceutical preparations were 100.7(S.E. 0.9), 99.5(0.8), 99.1(0.8) and 99.1%(O.9), respectively. The high accuracy and precision of this assay were inherent in the flame photometric detectors normally used in gas chromatography.

• YAKHAK HOEJI
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• v.35 no.4
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• pp.288-294
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• 1991

A new fluorescent derivatizing reagent was developed to be used in HPLC for the trace determination of primary and secondary amines. This new reagent, 1-(N,N-dimethylamino)pyrene-6-sulfonyl chloride, was synthesized by the chlorination of sodium 1-(N,N-dimethylamino)pyrene-6-sulfonate which was obtained from 1-(N,N-dimethylamino)pyrene after sulfonation. Ephedrine and norephedrine were derivatized quantitatively by this reagent. The optimum conditions for the derivatization such as pH, reagent concentration, reaction time and reaction temperature ware examined. The structures of derivatives were identified by IR, $^{1}$H-NMR and MS methods. The fluorescence properties and the stability of the derivatives were examined. The derivatives were separated on silica column with an isocratic elution using the mixture of n-hexane and ethylacetate and monitored by fluorescene detector. Linear calibration curves were obtained and detection limits in a 10 $\mu$l injection volume were 5 picomole for ephedrine and norephedrine.

• YAKHAK HOEJI
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• v.31 no.5
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• pp.330-337
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• 1987

The weak UV absorbing ephedrine alkaloids such as ephedrine, pseudoephedrine, methylephedrine and norephedrine could be analyzed by charge-transfer spectrophotometric method. The results obtained are summarized as follows: (1) It was possible to determine a weak UV absorbing ephedrine alkaloids using the intense charge-transfer UV bands in chloroform. (2) This method was suitable for the spectrophotometric determination of ephedrine alkaloids in mixed pharmaceutical preparation. (3) Linear relationship was found between absorbance and concentration in the range of 1.0$\times$$10^{-5}M$~5$\times$$10^{-5}M$ of ephedrine ($\varepsilon$= 2.72$\times$$10^{4}LM^{-1}cm^{-1}$ and pseudoephedrine ($\varepsilon$=2.84$\times$$10^{4]LM^{-1}cm^{-1}$), 1.0$\times$$10^{-5}M$~5$\times$$10^{-5}$M of methylephdrine ($\varepsilon$=1.68$\times$$10^{4}LM^{-1}cm^{-1}$) and 1/3$\times$$10^{-4}M$~4/3$\times$$10^{-4}M$ of norephedrine ($\varepsilon$=0.74$\times$$10^{4}LM^{-1}cm^{-1}$. (4) CT- complex of ephedrine, pseudoephedrine and methylephedrine has absorption maxima at 293nm and norephedrine have absorption maximum at 253nm. (5) CT-complexes were formed in a 1:1 ratio between ephedrine alkaloids and iodine in chloroform. (6) By UV, IR, and $^1H$-NMR spectra, it could be inferred that CT-complexes were formed by interaction between the basic nitrogen of ephedrine alkaloids as electron (n) donor and iodine as electron ($\sigma$) acceptor.

• Journal of the Korean Chemical Society
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• v.40 no.4
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• pp.287-290
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• 1996

• Korean Journal of Pharmacognosy
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• v.48 no.1
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• pp.93-96
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• 2017

Ephedra alkaloids, (-)-ephedrine, (+)-pseudoephedrine, (-)-N-methylephedrine, (+)-N-methylpseudoephedrine, (-)-norephedrine and (+)-norpseudoephedrine, from ephedra herb are sympathomimetic agonists causing an increase of metabolism, blood pressure and perspiration. In this study, we developed the validation method of (+)-pseudoephedrine and (-)-ephedrine, two major ephedra alkaloids in Ephedra spp., by high-performance liquid chromatography-ultraviolet spectrometer (HPLC-UV). HPLC analysis was performed using a HECTOR-M C18 column operating at $35^{\circ}C$, and UV detection at 215nm. The mobile phase used a gradient flow with 25 mM SDS in water (A) and acetonitrile (B).

• YAKHAK HOEJI
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• v.47 no.5
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• pp.266-270
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• 2003

We evaluated four commercially available methamphetamine immunoassays for their relative cross-reactivities of amphetamine analogues in human urine: Abbott TDx, Vitalab Selectra and on-site test kits (Accusign MET, SD bioline MET). High cross-reactivities were shown at designer's drugs such as methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA) and methylenedioxyethylamphetamine (MDEA) in all of the tested immunoassays. Methoxyphenamine, fenfluramine and phentermine were positive in TDx and Selectra, but were not positive in on-site test kits. Pseudoephedrine, norpseudoephedrine, ephedrine, norephedrine, MDMA, MDA, fenfluramine and phentermine were detected by gas chromatography/mass spectrometry(GC/MS) in false positive urines. Since the overall specificity of any of the devices was not 100％, we found it is important to confirm any positive screening test result, so we developed simultaneous determination of amphetamine analogues in urines. After alkalinization of the urine samples with 6-N NaOH, the analytes were extracted using ethyl acetate, derivatized with pentafluoropropyl anhydride (PFPA) prior at GC/MS analysis.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.401-404
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• 2001

A new chiral stationary phase (CSP) based on (1R,2S)-2-amino-1-indanol, which is expected to be conformationally rigid because of its cyclic nature, was prepared. The new CSP was applied in resolving various $N-acyl-\alpha-arylalkylamines$. The chromatographic resolution results on the new CSP were compared with those on the other CSP based on (1S,2R)-norephedrine, which is believed to be conformationally flexible. Comparison of the chromatographic resolution results on the two CSPs demonstrated that conformationally flexible analytes are resolved better on the conformationally rigid CSP while conformationally rigid analytes are resolved better on the conformationally flexible CSP. From these results it was concluded that conformational rigidity or flexibility of CSPs is the important factor for the chiral recognition.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1080-1084
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• 1994

Asymmetric inducing effects of substituents attached at nitrogen, the 5-position and boron in oxazaborolidine rings on asymmetric borane reduction of ketones were investigated. Thus, the effect of N-substituents examined with the oxazaborolidines prepared from (lR,2S)-N-alkyl norephedrine derivatives showed the remarkable decrease of enantioselectivities of the product alcohols by the variation of the steric size of alkyl groups on nitrogen from Me${\leftrightarro}$n-Bu(${\simeq}$Bn)${\leftrightarro}$ neopentyl${\leftrightarro}$i-Pr, such as 83${\%}$ ee with 5b, 22${\%}$ ee with 5c, 23${\%}$ ee with 5f, 16${\%}$ ee with 5e, and 3${\%}$ ee with 5d for the reduction of acetophenone. The presence of diphenyl groups at the 5-position enhanced the enantioselectivities dramatically. The effect of B-alkyl substituents in the oxazaborolidines derived from (lR,2S)-ephedrine showed that the enantioselectivities of product alcohols decreased gradually when the substituents were changed from hydrogen to steric bulky groups such as methyl, n-butyl, thexyl and phenyl.